anatomy cell

8/7/2019 anatomy cell

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S. Waldman CHEE 340

Basic Anatomy

The objective of this lecture is to describe some

important structures of the human body (anatomy) to

set the stage for where Biomedical Engineers work.


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Anatomical Directions

Directions (Absolute):

anterior/posterior

superior/inferior

medial/lateral

Directions (Relative):

proximal/distal


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Anatomical Planes

Planes:

Frontal or Coronal

Saggital

Transverse


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S. Waldman CHEE 340

Cells

Discovered more than 300 years ago after the discovery of the

microscope.

Cells are the smallest anatomical and physiological unit that can

live and reproduce on its own (under appropriate conditions).

Human red blood cells in the

lumen of an artery

Size: 10-15 Qm in diameter

3-5 Qm thick


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Cells

Lead to the cell theory which states:

All organisms are comprised of one or more cells

The cell is the smallest unit of life

All cells come from previously existing cells

Comprised of mostly organic compounds and water, theysynthesize various molecules fundamental for sustaining life:

Carbohydrates (polysaccharides)

structural materials, energy storage, etc.

Lipids (fat)

structural materials, energy storage, etc. Proteins (poly-amino acids)

enzymes, structural materials, signaling, transport channels, etc.

Nucleic Acids (DNA, RNA) and Nucleotides (ATP)

informational storage and energy


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S. Waldman CHEE 340

Cellular Structures (Eukaryotes)

Major Cell Structures:

Plasma Membrane

Cytoplasm

cytosol

organellescytoskeleton


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Plasma Membrane

Surrounding membrane of the cell

Major Functions:

Mechanical integrity

Aids in movement (motility)

Regulates the transport of chemicals/molecules


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S. Waldman CHEE 340

Plasma Membrane

Phospholipids have a polar head

(glycerol) and two non-polar tails(fatty acids).

Leads to a solubilty-challenged

molecule and when exposed to an

aqueous environment, form uniqueassemblies called bi-layers.

Polar heads of the phospholipids

turn toward the water molecules

(hydrophilic) while the non-polartails hide from water molecules

(hydrophobic).


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S. Waldman CHEE 340

Receptors

Plasma membrane is also interspersed with various proteins that

perform specific actions (membrane-bound receptors).

Ligand binding to a membrane-

bound receptor can elicit:

Coupling

Trafficking (channels)

Signaling


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Transport

Molecules can be transported across the cell membrane by one of

three ways: Passive diffusion (non-polar)

e.g. O2, CO2, H2O, some solutes by osmosis

Channels (small molecules)

Vesicles (large molecules)

endocytosis, exocytosis


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Channels

Channels serve to transport small molecules that cannot easily

diffuse across the cell membrane (polar molecules).

They also help to maintain

concentrations of ions andmolecules inside the cell

that are different than the

concentrations outside the

cell (active transport

requiringATP).


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S. Waldman CHEE 340

Ion Channels

12 mM [Na+]

125 mM [K+]

5 mM [Cl-]

108 mM [anions]

Cell Extracellular Fluid

120 mM [Na+]

5 mM [K+]

125 mM [Cl-]

Due to the difference in environments, ion channels also help to

maintain both an osmoticand electrical

balance between the celland the extracellular fluid.

Cells must expend energy to keep this balance and thus cells exist

at steady-state (not equilibrium).


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Cytoplasm

The internal contents of the cell is called the cytoplasm which is

comprised of: Cytosol(intracellular fluid)

Organelles (little structures that perform specific functions)


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Cytoskeleton

The cytoskeleton is another organelle that makes up the internal

support structure for the cell and is involved in: Cell shape

Cell movement (motility)

Intracellular movement


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S. Waldman CHEE 340

Tissues

A group of cells and surrounding substances that function togetherto perform one or many specialized activities is called a tissue.

Four primary types of tissues:

Epithelial

Connective

Muscle

Nervous


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S. Waldman CHEE 340

Epithelial Tissues

Either composed of cells arranged in sheets (one or more layersthick) or organized into glands that are adapted for secretion.

Functions include:

Absorption (lining of the small intestine)

Secretion (glands)

Transport (kidney tubules)

Protection (skin)

Sensory receptors (taste buds)


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Epithelial Tissues


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Connective Tissues

Most abundant and widely distributed class of tissues which aretypically acellular.

Many classifications:

Loose (loosely woven fibres that surround organs)

Irregularly dense (protective capsules around organs)

Regularly dense (ligaments, tendons)

Specialized (blood, cartilage, bone, fat)


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Connective Tissues


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Muscle Tissue

Muscle consists of specialized cells that can shorten in response toelectrical stimulation.

Three types of muscle tissues:

Cardiac (heart)

Smooth (walls of blood vessels, orifices)

Skeletal (attached to bones)


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Muscle Tissue


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Nervous Tissue

Nerves are conduits that serve to transmit signals to other parts ofthe body.

Nervous tissue is comprised of:

Neurons (specialized cells that transmit electrical impulses)

Glial cells (cells that support, protect and nourish the neurons)


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Nervous Tissue


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Summary

Cells are the smallest anatomical and physiological unit

of the body.

Tissues are group of cells, together with the

substances they produce (i.e. protein, carbohydrates,lipids), that perform a set of coordinated actions.

anatomy cell

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